CL77 Selenium Rectifier upgrade

David M. Lyon · Post by **David M. Lyon** » Mon Oct 02, 2017 1:17 pm

I was having battery charging problems and low voltage from the original rectifier and the battery kept going down overnight so I knew it had to be bad rectifier. I wanted to keep the original look if possible, so after I read the post about using the Radio Shack diode type Bridge rectifier I figured a way to keep it as original as possible and still have a modern solid state bridge. After installing the new diode bridge the battery stays charged and now I can actually run my headlight. I didn't dare turn it on before!
Here is a YouTube video of what I did.

https://youtu.be/YgTsb3yDT8s

oldbikedude · Post by **oldbikedude** » Mon Oct 02, 2017 6:39 pm

Great idea! I might have to copy you. Thanks for sharing the video.

brewsky · Post by **brewsky** » Wed Oct 04, 2017 7:03 am

I love it!

Looks like you just increased the price of old bad rectifiers!

Only thing, you should be getting more than 12.3V at higher rpm.....more like 14.

12.7 is commonly spec'd as full battery charge %.

David M. Lyon · Post by **David M. Lyon** » Wed Oct 04, 2017 9:13 am

Yeah. I was just getting voltage reading at the Battery with the engine at an idle. Prior to the upgrade it wouldn't maintain 12 volts at ANY RPM. The battery was supplying voltage to run and the battery was NOT being maintained. Then when I cut the headlamp on it dropped to 10.8 volts and went dead QUICK! The rectifier wasn't functioning at all. ....At around 3000 RPM I get about 13.5 volts which should maintain a fully charged battery.

brewsky · Post by **brewsky** » Wed Oct 04, 2017 10:11 am

Good deal....I'm on the way now to find my old rectifier!

G3 · Post by G3 » Wed Oct 04, 2017 9:14 pm

David,

Brilliant idea in order to keep the OEM image intact. But my question is regarding the air cleaners on your Scrambler: Is there some reason you've cut off 2 to 3" of air cleaner element?

David M. Lyon · Post by **David M. Lyon** » Wed Oct 04, 2017 10:02 pm

I wanted to use some modern elements and get away from the old style paper type filters, so I located a couple of Filters with the same oval shape and size and glued them to the original filter shells with Epoxy. I just didn't want to trust a new bore, piston and rings rebuild to the old style air filters. With the side tanks in place you can't tell they are any different from the original because I used the original shell metal.